/Recent content on Mateus MercerHugoen-USMateus Mercer - {year}<br>🌎Sat, 11 Apr 2026 00:00:00 +0000/gold/compart/Sat, 11 Apr 2026 00:00:00 +0000/gold/compart//gold/vole-wtf/Sat, 11 Apr 2026 00:00:00 +0000/gold/vole-wtf//posts/ubuntu-on-android/Sun, 15 Feb 2026 12:23:11 -0300/posts/ubuntu-on-android/<p><div class="text-center my-4"> <img src="images/rambotux.png" alt="A Linux Tux penguin with a Rambo costume (red bandanna) with a huge rifle after destroying a computer CRT monitor." title="A Linux Tux penguin with a Rambo costume (red bandanna) with a huge rifle after destroying a computer CRT monitor." class="img-fluid rounded" loading="lazy"> <p class="fst-italic my-2 mx-auto small img-desc">This <span class="sidenote"> <label class="sidenote-label" for="sidenote-0">2000&#39;s Linux era vibes</label> <input class="sidenote-checkbox" type="checkbox" id="sidenote-0"> <span class="sidenote-content sidenote-right"> Did you ever search for &ldquo;Rambo Tux&rdquo;? Those images are a journey, not gonna lie. </span> </span> image was probably <a href="https://tineye.com/search/fa80eaaf39547be7b951d8c3b374ebf3f6ca33b0?tags=&amp;show_unavailable_domains=true&amp;sort=crawl_date&amp;order=asc&amp;page=1" class="matbm-hoverable" id="link-7e80c52a0" target="_blank" rel="noopener">created by the author of a bulgarian blog lost to time.</a> I always thought that the <a href="https://linux-hardware.org/" class="matbm-hoverable" id="link-99d847b6c" target="_blank" rel="noopener">Linux hardware probe logo</a> was funny and weird and decided to investigate.</p>/gold/redblob/Wed, 28 Jan 2026 00:00:00 +0000/gold/redblob//toolbox/archivers/keka/Sat, 19 Jul 2025 00:00:00 +0000/toolbox/archivers/keka/<p>Obsidian is a powerful knowledge management tool that treats your notes as a connected web of information. It&rsquo;s designed for people who want to build a comprehensive personal knowledge base.</p> <h2 id="features">Features</h2> <ul> <li><strong>Bidirectional linking</strong> between notes</li> <li><strong>Graph view</strong> to visualize note relationships</li> <li><strong>Plugin ecosystem</strong> for extending functionality</li> <li><strong>Themes and customization</strong> options</li> <li><strong>Local storage</strong> - your data stays on your device</li> <li><strong>Canvas feature</strong> for visual brainstorming</li> </ul> <h2 id="best-for">Best For</h2> <ul> <li>Researchers and students building knowledge bases</li> <li>Writers working on complex projects</li> <li>Anyone who wants to connect ideas across notes</li> <li>People who prefer local file storage over cloud solutions</li> </ul> <h2 id="getting-started">Getting Started</h2> <ol> <li>Download and install Obsidian</li> <li>Create your first vault (note repository)</li> <li>Start writing notes using markdown syntax</li> <li>Use [[double brackets]] to link between notes</li> <li>Explore the graph view to see connections</li> <li>Browse community plugins to enhance functionality</li> </ol>/toolbox/productivity/obsidian/Sat, 19 Jul 2025 00:00:00 +0000/toolbox/productivity/obsidian/<p>Obsidian is a powerful knowledge management tool that treats your notes as a connected web of information. It&rsquo;s designed for people who want to build a comprehensive personal knowledge base.</p> <h2 id="features">Features</h2> <ul> <li><strong>Bidirectional linking</strong> between notes</li> <li><strong>Graph view</strong> to visualize note relationships</li> <li><strong>Plugin ecosystem</strong> for extending functionality</li> <li><strong>Themes and customization</strong> options</li> <li><strong>Local storage</strong> - your data stays on your device</li> <li><strong>Canvas feature</strong> for visual brainstorming</li> </ul> <h2 id="best-for">Best For</h2> <ul> <li>Researchers and students building knowledge bases</li> <li>Writers working on complex projects</li> <li>Anyone who wants to connect ideas across notes</li> <li>People who prefer local file storage over cloud solutions</li> </ul> <h2 id="getting-started">Getting Started</h2> <ol> <li>Download and install Obsidian</li> <li>Create your first vault (note repository)</li> <li>Start writing notes using markdown syntax</li> <li>Use [[double brackets]] to link between notes</li> <li>Explore the graph view to see connections</li> <li>Browse community plugins to enhance functionality</li> </ol>/toolbox/screenshot/sharex/Sat, 19 Jul 2025 00:00:00 +0000/toolbox/screenshot/sharex/<p>ShareX is a free and open-source program that lets you capture or record any area of your screen and share it with a single press of a key. It&rsquo;s one of the most comprehensive screenshot tools available for Windows.</p> <h2 id="features">Features</h2> <ul> <li><strong>Screen capture</strong> (fullscreen, window, monitor, region, scrolling capture)</li> <li><strong>Screen recording</strong> with customizable settings</li> <li><strong>Auto-upload</strong> to over 80 destinations including cloud services</li> <li><strong>Built-in tools</strong> like image editor, color picker, ruler, and more</li> <li><strong>Workflow automation</strong> with custom actions</li> <li><strong>Hotkey support</strong> for quick access</li> </ul> <h2 id="best-for">Best For</h2> <ul> <li>Windows users who need comprehensive screenshot functionality</li> <li>Users who want to automate their screenshot workflow</li> <li>Anyone looking for a free alternative to paid screenshot tools</li> </ul> <h2 id="getting-started">Getting Started</h2> <ol> <li>Download from the official website</li> <li>Install and launch ShareX</li> <li>Use <code>PrintScreen</code> to capture your screen</li> <li>Configure upload destinations if needed</li> <li>Explore the various capture modes and tools</li> </ol>/posts/how-to-upgrade-debian-buster-bookworm/Sun, 28 Jan 2024 02:00:05 -0300/posts/how-to-upgrade-debian-buster-bookworm/<p><div class="text-center my-4"> <img src="images/software-maintenance-crop.jpg" alt="A reference to heart rate monitor with black and red colors" title="A reference to heart rate monitor with black and red colors" class="img-fluid rounded" loading="lazy"> <p class="fst-italic my-2 mx-auto small img-desc">A reference to heart rate monitor with black and red colors. Source: <a href="https://archive.org/details/softwaremaintena0000unse_j8i4" class="matbm-hoverable" id="link-154c20562" target="_blank" rel="noopener">Internet Archive, Software maintenance and computers, 1990</a> .</p> </div> </p> <h1 id="overview">Overview</h1> <p>It&rsquo;s not permitted to jump Debian releases, so we need to upgrade two times, from Debian 10, to 11, then 12.</p> <p>My server has 4 main apps:</p>/posts/limiting-single-program-memory-usage-with-cgroups-in-linux/Sun, 28 May 2023 04:16:46 -0300/posts/limiting-single-program-memory-usage-with-cgroups-in-linux/<p><div class="text-center my-4"> <img src="images/computer-eating-memory.jpg" alt="A computer eating a floppy disk" title="A computer eating a floppy disk" class="img-fluid rounded" loading="lazy"> <p class="fst-italic my-2 mx-auto small img-desc">A hungry computer eating a floppy disk. Source: <a href="https://archive.org/details/197708ROMV1I02/" class="matbm-hoverable" id="link-bcc561dc4" target="_blank" rel="noopener">Internet Archive, ROM magazine, 1977</a> , illustrated by <a href="https://www.robertgrossman.com/" class="matbm-hoverable" id="link-1c8027eae" target="_blank" rel="noopener">Robert Grossman</a> .</p> </div> </p> <h2 id="trying-to-do-it-with-ulimit">Trying to do it with <code>ulimit</code></h2> <p>While trying to solve the <a href="https://osprogramadores.com/desafios/d07/" class="matbm-hoverable" id="link-743fcc6c5" target="_blank" rel="noopener">07 challenge from Os Programadores</a> (and validating other&rsquo;s solutions), I had to check if my (and other&rsquo;s) program used less than 512 megabytes of memory.</p> <p>OK, the instructions page for the challenge told me to use <code>ulimit -v 524288</code> to test it.</p>/posts/hello-world/Sun, 12 Sep 2021 18:45:34 -0300/posts/hello-world/<p><div class="text-center my-4"> <img src="images/hello-world.jpg" alt="A world made of computer chips" title="A world made of computer chips" class="img-fluid rounded" loading="lazy"> <p class="fst-italic my-2 mx-auto small img-desc">A world made of computer chips. Source: <a href="https://archive.org/details/80_Microcomputing_Issue_23_1981-11_1001001_US/mode/2up" class="matbm-hoverable" id="link-8e7084ff3" target="_blank" rel="noopener">Internet Archive &lt;3</a></p> </div> </p> <p class="first-paragraph-dropcap">Hello World! For a developer, this is such a common thing to say when starting a new project.</p> <p>Not only humans say hello, actually in SMTP protocol, it starts an e-mail exchange by sending <code>HELO</code><sup id="fnref:1"><a href="#fn:1" class="footnote-ref" role="doc-noteref">1</a></sup>. So you can imagine that millions, if not billions of &ldquo;Hello&rsquo;s&rdquo; are sent everyday by machines.</p>